This invention relates generally to the field of surgery, and more particularly to the field of vascular microsurgery.
In various surgical procedures, it is necessary to unite or reunite very small blood vessels, nerves and the like. The procedure of joining blood vessels is known as vascular anastomosis. Particularly in neurosurgical procedures and in the reattachment of severed body members, the number of anastomoses required can be very numerous, and accordingly, it is advantageous and frequently necessary to perform each such connection quickly yet properly.
A conventional end-to-end anastomosis is illustrated in FIG. 1, which shows a pair of vessels 1 and 2, each held by a respective clamp 3 or 4 while it is sutured around its circumference. The vessel ends are first approximated by inward traction on the two vascular clamps. The vessels may then be preliminarily interconnected by placing sutures at two, three or four spaced locations around the circumference of the vessel--note the threads 5 and 6 in tension--whereafter the suturing 7 is completed with a needle 8. Various suturing techniques are known, all of which are designed to: (a) provide a leak-proof connection; (b) provide adequate tensile strength; (c) avoid unnecessary restriction of the vessel; (d) avoid unnecessary tearing and other trauma to the vessel; and (e) promote rapid and thorough healing. Some of these objectives become increasingly difficult to satisfy as smaller and smaller anastomoses are carried out; furthermore, the danger of accidentally catching the rear or distal wall of a vessel with the needle as the proximal wall is being sutured increases with diminishing vessel sizes.
With all vascular suturing techniques, thrombosis or clotting tends to occur at the points of needle penetration. While this clotting would not usually be sufficient to occlude larger vessels, in smaller veins and arteries a significant constriction or complete occlusion of the vessel can result from clotting. The problem has been summarized thus: "It is apparent to us that the damage to vascular endothelium caused by the microvascular needle perforation is considerable. The amount of subsequent platelet aggregation and clot formation can be extensive, and these platelets are known to release vasoactive substances that can alter vessel diameter. This could diminish blood flow through a 1- to 2-mm vascular anastomosis expected to give immediate increased flow to an underperfused region of the brain." D. Pagnanelli et al, The Cutting Edge Microsurgical Needle, Journal of Neurosurgery, volume 59, no. 3, pages 510-512 (Sept. 1983).
In addition to the physiological damage done by suturing, it is also significant that suturing, particularly of small vessels, is a very tedious time-consuming procedure which can preoccupy and fatigue a surgeon over the course of a long procedure. A more rapid way of performing microvascular anastomoses could free the surgeon for other tasks, and could shorten surgical procedures as well. The need for a workable, rapid, non-suturing technique for microsurgery is obvious.
Various non-suture devices and techniques for performing anastomoses are known, particularly for intestinal and colorectal anastomoses, for which various stapling apparatus and methods have been known for some years. Known stapling techniques, however, require penetration of the organ wall, and if applied to vascular anastomoses, the problems of clotting and the like, as described above, could be expected to arise. For vascular anastomosis, various other non-suture mechanical clamps have been suggested. Such clamps frequently include a permanent or sacrificial ferrule or the like and means for clamping the vessel against the ferrule so that penetration of the vessel wall is avoided. However, clamps of this type have not gained widespread acceptance.
In view of the foregoing, this invention has been made with a view to substantially increasing the speed of microvascular anastomoses and other procedures while avoiding the clotting problems caused by conventional suturing procedures. Another object is to reduce the material costs and duration of microsurgical procedures.
A further object of the invention is to provide a permanently implantable surgical clip for use in place of microvascular suturing. Yet another object is to provide the surgeon with a clip that can be easily held and applied during vascular anastomoses.
This invention relates generally to a surgical procedure such as an anastomosis wherein a pair of tissues is approximated, then partially everted, and then joined by placing the arms of a surgical clip over the adjoined tissues and crimping the arms about the tissues in such a way as to hold the tissues together without penetrating them.
The invention is also directed to a vascular surgical clip comprising a plastically deformable body portion, a tang for deforming the body, and a neck connecting the tang to the body, wherein the neck is designed to break upon application of a predetermined tensile force to the tang, and the body being designed to deform upon application to the tang of less than said predetermined tensile force.
In a further aspect, the invention is directed to a tool for applying the subject clip. In its broadest sense, the tool includes means for gripping and applying tension to the tang, and means for simultaneously pushing against shoulders on the clip body. The tool enables the surgeon to perform the subject method by using the tool first to manipulate the clip into position over opposed tissues. Then, by squeezing or otherwise manipulating the tool, he deforms the clip so as to capture the tissues between the clip's arms and thereby hold the tissues permanently together.